Preparation Of Metallic Monolithic Catalyst By Spraying And Its Performance Of Catalytic Combustion Of VOCs

Catalytic combustion can be considered an effective method to eliminate VOCs emissions,since its low energy cost and thermal NO_x emissions,high removal efficiency,and high adaptability.Monolithic catalysts are widely used in catalytic combustion because of their good attrition resistance and very low pressure drop in the high flows.Metallic substrate is a superior monolithic support with a high mechanical resistance,an excellent electrical and thermal conductivity and a low manufacturing cost.However,the preparation flow of the metallic monolithic catalyst is cumbersome,wash-coating methods of metallic substrates are complex and it have poor adhesion of coatings.Moreover,the conventional technologies of catalytic combustion usually require an external heat source,this requirement slows combustion launch.Therefore,it is of great practical significance to investigate and develop metallic monolithic catalysts with simple preparation method,well-adhered wash-coating,and rapid catalytic combustion launch.In this paper,the solvent-thermal method was used to prepare monodisperse Pt nanoparticles sol with noble metal salt as precursors,oleylamine and oleic acid as surfactants and solvents.And the FeCrAl monolithic catalyst with a loading of 0.1wt%was prepared by a novel spraying technique and the noble metal nanosol particles were uniformly loaded onto FeCrAl fiber?calicined at 950°C for 3 h under O₂ atmosphere?.Simple spraying can be easily to achieve species,and it can take full advantage of reactor space.In addition,the catalyst exhibited high catalytic activity and good stability,it can completely convert toluene to CO₂ and H₂O at 260°C and there is no decrease in catalytic activity during the 600 min on-stream reaction.TEM,SEM,and XRD confirmed that the noble metal nanoparticles can be highly dispersed on the surface of FeCrAl fiber and exhibit extremely excellent surface adhesion properties.The superior properties can be attributed to the well-adhered alumina coating that formed on the surface of the FeCrAl fiber after thermal treatment and the self-dispersion of Pt nano-colloidal particles.To solve the problem of slow launch of catalytic combustion reaction,the high-resistance FeCrAl metal wire was selected a support and calcined at 950°C for 3h under O₂ atmosphere,the electrically heated monolithic Pt or Pd catalysts were also prepared by noble metal nanosol spraying technique.We utilized the excellent electrically heated characteristics of FeCrAl wire,and FeCrAl wire was connected to the DC power.The metallic monolith then rapidly self-heated until reaching the light-off temperature required for VOCs combustion.The monolithic catalysts exhibited nearly 100%toluene and ethyl acetate conversion rates and CO₂ selectivity under DC power of 5 W and 8 W with the combustion response time of less than 30 s.Moreover,the monolithic catalysts presented an excellent activity at a rather high space velocity,it can be used to catalyzed the combustion of high-flux VOCs.Furthermore,the monolithic Pt or Pd catalysts showed the superior catalytic activity for hydrocarbon,oxygenates and heteroatom VOCs combustion,it demonstrated that electrically heated metallic monolithic catalyst has favourable industrial application scenarios for VOCs removal under certain conditions.